AGE LIMITS OF THE GREENSTONE BELTS OF THE WESTERN ALDAN SHIELD

Abstract

The main features in the geological structure of the western Aldan Shield are largely determined by nearly meridional and NE-trending fault zones that host numerous tectonic fragments composed of weakly metamorphosed volcanosedimentary rocks of the Saimagan, Tarynakh, Tokko-Khanin, Itchilyakh, Evonokit, Temulyakit, Tungurcha, Yaelakh, Subgan, Bulgunyakhtakh, and Balaganakh greenstone belts. At present, most researchers believe that these tectonic fragments were formed during the Late Archean stage of the Aldan Shield evolution. However, reliable geochronological and isotopic-geochemical data are currently available only for the Tokko-Khanin greenstone belt. In order to fill this gap in our knowledge of the region, we performed Sm-Nd isotopic studies of clastic metasedimentary and metavolcanic rocks from the greenstone belts in the western Aldan Shield.